#include <stdio.h>
#include <float.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

double min = 90000;
double max = 3000000;

int parse_double(const char *str, double *res) {
	char *ptr;

	*res = strtod(str, &ptr);
	if (*ptr)
		return 0;

	return 1;
}

void print(double diff, double val) {
	int lvl = (int)round((val - min + 1) / diff * 7);
	if (lvl < 0)
		lvl = 0;

	else if (lvl > 7)
		lvl = 7;

	putchar('\xe2');
	putchar('\x96');
	putchar('\x81' + lvl);
}

int main(int argc, char **argv) {
	argv++;
	argc--;

	if (argc == 0) {
		fprintf(stderr, "spark: missing operands\n");
		return 1;
	}

	size_t as = argc / 2;
	double *a = malloc((as + 1) * sizeof(double));
	if (a == NULL)
		return 1;

	size_t j = 0;
	for (size_t i = 0; i < as; i++) {
		double val = 0;
		if (!parse_double(argv[j], &val)) {
			j++;
			continue;
		}

		double val2 = 0;
		if (!parse_double(argv[j + 1], &val)) {
			j++;
			continue;
		}

		a[i] = (val + val2) / 2;
		j++;
	}

	double diff = max - min + 1;
	if (diff < 1)
		diff = 1;

	for (size_t i = 0; i < as; i++)
		print(diff, a[i]);

	putchar('\r');

	free(a);
	return 0;
}